diff options
Diffstat (limited to 'modules')
| -rw-r--r-- | modules/CheckAtomic.cmake | 64 |
1 files changed, 34 insertions, 30 deletions
diff --git a/modules/CheckAtomic.cmake b/modules/CheckAtomic.cmake index 900ae7e0..41cff207 100644 --- a/modules/CheckAtomic.cmake +++ b/modules/CheckAtomic.cmake @@ -27,8 +27,12 @@ function(check_working_cxx_atomics varname) check_cxx_source_compiles(" #include <atomic> std::atomic<int> x; + std::atomic<short> y; + std::atomic<char> z; int main() { - return std::atomic_is_lock_free(&x); + ++z; + ++y; + return ++x; } " ${varname}) set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS}) @@ -43,50 +47,50 @@ function(check_working_cxx_atomics64 varname) std::atomic<uint64_t> x (0); int main() { uint64_t i = x.load(std::memory_order_relaxed); - return std::atomic_is_lock_free(&x); + return 0; } " ${varname}) set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS}) endfunction() - -# This isn't necessary on MSVC, so avoid command-line switch annoyance -# by only running on GCC-like hosts. -if (LLVM_COMPILER_IS_GCC_COMPATIBLE) +# Check for (non-64-bit) atomic operations. +if(MSVC) + set(HAVE_CXX_ATOMICS_WITHOUT_LIB True) +elseif(LLVM_COMPILER_IS_GCC_COMPATIBLE) # First check if atomics work without the library. check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB) # If not, check if the library exists, and atomics work with it. if(NOT HAVE_CXX_ATOMICS_WITHOUT_LIB) - check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC) - if(HAVE_LIBATOMIC) - list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") - check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB) - if (NOT HAVE_CXX_ATOMICS_WITH_LIB) - message(FATAL_ERROR "Host compiler must support std::atomic!") - endif() - else() - message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.") - endif() + check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC) + if(HAVE_LIBATOMIC) + list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") + check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB) + if (NOT HAVE_CXX_ATOMICS_WITH_LIB) + message(FATAL_ERROR "Host compiler must support std::atomic!") + endif() + else() + message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.") + endif() endif() endif() # Check for 64 bit atomic operations. if(MSVC) set(HAVE_CXX_ATOMICS64_WITHOUT_LIB True) -else() +elseif(LLVM_COMPILER_IS_GCC_COMPATIBLE) + # First check if atomics work without the library. check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITHOUT_LIB) -endif() - -# If not, check if the library exists, and atomics work with it. -if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB) - check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64) - if(HAVE_CXX_LIBATOMICS64) - list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") - check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB) - if (NOT HAVE_CXX_ATOMICS64_WITH_LIB) - message(FATAL_ERROR "Host compiler must support std::atomic!") - endif() - else() - message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.") + # If not, check if the library exists, and atomics work with it. + if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB) + check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64) + if(HAVE_CXX_LIBATOMICS64) + list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") + check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB) + if (NOT HAVE_CXX_ATOMICS64_WITH_LIB) + message(FATAL_ERROR "Host compiler must support 64-bit std::atomic!") + endif() + else() + message(FATAL_ERROR "Host compiler appears to require libatomic for 64-bit operations, but cannot find it.") + endif() endif() endif() |